Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2020	Jul. 31, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Trading Symbol	PBYI
Entity Registrant Name	PUMA BIOTECHNOLOGY, INC.
Entity Central Index Key	0001401667
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		39,676,779
Entity File Number	001-35703
Entity Tax Identification Number	77-0683487
Entity Address, Address Line One	10880 Wilshire Boulevard
Entity Address, Address Line Two	Suite 2150
Entity Address, City or Town	Los Angeles
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	90024
City Area Code	424
Local Phone Number	248-6500
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Document Quarterly Report	true
Document Transition Report	false